Answer:
140,000.
Step-by-step explanation:
The ratio 5:2 can be expanded to 10:4 (just multiplying them by 2 to make it easier), making the 350,000 births now 700,000 births. 10 / 4 = 2.5 making us divide 700,000 by 2.5. That would give us 280,000, however, this is regarding the ratio of 10:4 and not 5:2, so you divide 280,000 by 2 and you would get your answer, 140,000.
I think this is the answer, sometimes I'm not the smartest but that's the best I can give you. Also, this is probably not the easiest way to get the answer.
